This is a wonderful interactive chart that shows you how worthwhile (or worthless) certain supplements are, based on evidence (as opposed to anecdote or worse): Snake Oil Supplements from Information is Beautiful.
If you are a fan of a certain supplement, you can use this chart to discover what it is good for. And if you have a certain health concern, you can use the chart to determine what may work and what’s a waste of money.
If you like this, check out more of the charts on the information is beautiful site. They have lots of good charts.